1. Field of the Invention
The present invention relates to Schottky barrier diodes and, more particularly, to a Schottky barrier diode with reduced parasitic capacitance, a method of forming the diode and a design structure for the diode.
2. Description of the Related Art
A Schottky barrier diode is a rectifying element created by a potential barrier, which is formed at the junction between a semiconductor surface and a metal layer on that surface. Schottky barrier diodes typically exhibit relatively low forward voltage drops and relatively fast switching speeds as compared to conventional P-N junction diodes. However, they also typically exhibit a relatively high electric field around the outer edge of the semiconductor-metal junction. This electric field can negatively impact device performance (e.g., can lower breakdown voltage and/or can increase reverse bias leakage current). To reduce or eliminate this electric field, Schottky barrier diodes often incorporate a guardring to border the outer edge of the semiconductor-metal junction, where the semiconductor has a first conductivity type and the guardring has a second conductivity type that is different from the first conductivity type. For example, a P-type guardring can surround an N-type semiconductor-metal junction or an N-type guardring can surround a P-type semiconductor-metal junction. Unfortunately, such a guardring also introduces parasitic capacitance into the device (e.g., between the second conductivity type guardring and the first conductivity type semiconductor below the semiconductor-metal junction).